From Daily Writing Tips:
Reader ApK has asked for a discussion of the words sarcastic, sardonic, and facetious—
all examples of verbal irony.
verbal irony: the expression of one’s meaning by using language that normally signifies the opposite, typically for humorous or emphatic effect.
Sarcastic derives from the noun sarcasm.
sarcasm: a sharp, bitter, or cutting expression or remark; a bitter gibe or taunt.
Both the noun and the adjective derive from a Greek verb that had the meanings “to tear flesh, gnash the teeth, speak bitterly.”
Among the usual synonyms for sarcastic and sardonic are words that conjure up hurt and pain: caustic, scathing, trenchant, cutting, biting, sharp, acerbic.
caustic: burning, corrosive, destructive of organic tissue
scathing: from the verb “to scathe”: to injure, hurt, damage
trenchant: having a sharp edge, for cutting
acerbic: bitter, sharp, cutting
Sardonic does not have a corresponding noun in modern English, but it does derive from a Latin noun, sardonius, a poisonous plant that grew on the island of Sardinia. This plant was said to produce facial convulsions resembling horrible laughter, usually followed by death.
Link to the rest at Daily Writing Tips